Sampling Method
Every seventh name is called from a list of cooks.
Systematic
A nurse asks patients who bought the new wheel chair if they like the colours of the chairs. What is the population?
Patients who bought the wheel chair.
The entire group being studied.
Population
What colour shirt is Mr Lane wearing today?
Navy blue
Citizens write a question on a slip of paper and put it in a hat. The mayor draws a question to discuss.
Random Sampling
A Bunnings manager asks the last 5 people that used a new mower if they liked it. What is the sample?
The last 5 people who used the new mower.
The sub group who is actually being surveyed.
Sample
What is 8 x 9?
72
We survey 10% of the students randomly selected from each of grades 9, 10, 11 and 12.
Stratified
Students measure their foot length with a ruler, starting at the edge of the ruler (before 0cm). What kind of bias is this?
Measurement bias
An issue with a survey or data collection resulting in skewed results?
Bias
How old am I?
42
We select 5 classes at random, and survey every student in each of the 5 classes.
Cluster Sample
The real-estate agent asks the first 5 couples if they were interested in the house after an open house. What is the population and sample?
Population: all couples who went to the open house; Sample: the 5 couples s/he asked.
Every nth member of the population is selected.
Systematic Sampling
What date is the next student free day?
August 30
A radio show is doing a phone in survey to find out is listeners support a change to daylight savings.
Self-selected Sample
The principal asked the first 10 students who entered the school if they liked school. What is the possible bias?
Possible Bias: The first students who entered the school are more likely to like school.
Type of sampling at random from sub groups.
Stratified Sampling
How many days of classes are left this term (not including today)?
10